Even if you aren't in charge of the lighting design of a giant building, there's a valuable lesson here for anyone getting involved with smart home/building technology: make technology an addition to your setup, not a dependency. You still need to install physical light switches in every room, but as a bonus, you can pick light switches that are also controllable via some kind of network. All sorts of smart light switches meet this requirement—normal paddles or even toggles that can also be controlled via Zigbee, Z-Wave, Bluetooth, Wi-Fi, probably Ethernet, or whatever you want. This way, if the Internet is down, or some server explodes, or some cloud company shuts down, the lights will still work.

What you definitely shouldn't do is hard-wire the electricity to be always on and then hope the network to the light fixtures or light bulbs will be around to power them off. That's apparently what happened at this school, and now taxpayers are paying the price.